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    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
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    <title>Document</title>
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        document.write("<h1>我是内嵌的一级标题</h1>")
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<body>
    <button onclick="console.log('第一个js代码')">点我</button>
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